A control system for a driven rear axle, a driven rear axle and a method of controlling a driven rear axle

Abstract

The application provides a control system of a driven rear axle, a driven rear axle and a control method of the driven rear axle, and relates to the field of driven rear axles.The main oil cylinder comprises a main oil cavity one, a main oil cavity two, a main oil cavity three and a main oil cavity four, the main oil cavity one and the main oil cavity four are communicated through a steering gear control valve, the steering gear control valve can switch the oil inlet and the oil return of the main oil cavity one and the main oil cavity four, and the steering gear control valve is communicated with an oil tank;the piston rod of the centering oil cylinder is used to be connected with a steering knuckle arm of the rear axle, the centering oil cylinder comprises a secondary oil cavity one, a secondary oil cavity two, a secondary oil cavity three and a secondary oil cavity four, the secondary oil cavity one and the main oil cavity two are communicated through the control valve group, the secondary oil cavity two and the main oil cavity three are communicated through the control valve group, and the secondary oil cavity three and the secondary oil cavity four are communicated.The application can make the vehicle follow the active steering of the front axle, is suitable for highway and off-road working conditions, and is suitable for steering in low-speed working conditions below 60km / h.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of driven rear axle, in particular to a control system of driven rear axle, driven rear axle and driven rear axle control method. BACKGROUND

[0002] 10×4 multi-axle vehicle, because the number of its axle is more, its turning radius is relatively large, the whole vehicle passability is relatively poor. In order to solve the problem, the domestic and foreign generally adopts one two five bridge steering, three four bridge driving solution, wherein one, two, five bridge are driven axle, and the first two bridge adopts the way of "mechanical linkage + hydraulic boost" to realize accurate steering control, the steering mode of the fifth bridge generally adopts follow-up steering.

[0003] But in the case of fifth bridge follow-up steering scheme, the tire relies on the friction force of the ground to turn, causing the tire to wear quickly. SUMMARY

[0004] In order to solve the above technical problem of the prior art that the driven axle follows the steering tire and wears quickly, the present application provides a control system of driven rear axle, driven rear axle and driven rear axle control method, which can make the rear axle of the vehicle rely on the driving force of the front axle to realize active steering, and avoid relying on the friction force of the ground to turn, thereby avoiding the rapid wear of the tire.

[0005] The technical scheme adopted by the present application to solve the above technical problem is: a control system of driven rear axle, comprising an active oil cylinder and a centering oil cylinder, the piston rod of the active oil cylinder is used to connect with the swing arm of the steering system, the active oil cylinder comprises a main oil cavity one, a main oil cavity two, a main oil cavity three and a main oil cavity four, the main oil cavity one and the main oil cavity four are communicated through a steering gear control valve, the steering gear control valve can switch the oil inlet and oil return of the main oil cavity one and the main oil cavity four, and the steering gear control valve is communicated with an oil tank; the piston rod of the centering oil cylinder is used to connect with the steering knuckle arm of the rear axle, the centering oil cylinder comprises a secondary oil cavity one, a secondary oil cavity two, a secondary oil cavity three and a secondary oil cavity four, the secondary oil cavity one and the main oil cavity two are communicated through the control valve group, the secondary oil cavity two and the main oil cavity three are communicated through the control valve group, and the secondary oil cavity three and the secondary oil cavity four are communicated.

[0006] Through the cooperation of the active oil cylinder and the centering oil cylinder, the active oil cylinder can drive the centering oil cylinder to act during steering, so as to realize the active steering of the driven rear axle and avoid the passive steering of the driven axle under the action of the road friction force, thereby avoiding the wear of the tire.

[0007] Further, the control valve group comprises solenoid valve one and solenoid valve three, the main oil cavity two is communicated with the secondary oil cavity one through the solenoid valve one, and the main oil cavity three is communicated with the secondary oil cavity two through the solenoid valve three.

[0008] Further, the accumulator is further included, the auxiliary oil cavity three and the auxiliary oil cavity four are communicated with the accumulator respectively, the floating piston one and the floating piston two are arranged in the cylinder body of the centering oil cylinder, the piston rod of the centering oil cylinder penetrates the floating piston one, the floating piston one is located in the auxiliary oil cavity three, the limiting block is arranged in the cylinder body of the centering oil cylinder, the floating piston one and the floating piston two can abut on both sides of the limiting block, the floating piston two is arranged in the auxiliary oil cavity four, the control valve group further includes the electromagnetic valve two, the main oil cavity two and the main oil cavity three are communicated through the electromagnetic valve two.

[0009] The accumulator, the floating piston one and the floating piston two are matched, so that the piston rod of the centering oil cylinder can be limited, the centering oil cylinder is ensured to be in the middle position, the rear axle is not controlled to turn, the working conditions of the whole vehicle straight running and high-speed running are suitable, and wear caused by tire deflection of the rear axle and the difficulty of controlling the whole vehicle are avoided.

[0010] Further, the centering oil cylinder is provided with a stroke sensor.

[0011] The stroke sensor can sense the position of the piston rod of the centering oil cylinder, so that whether the rear axle wheel is deflected and the deflection direction are judged, closed-loop control is formed, and the working reliability and accuracy of the system are improved.

[0012] Further, the oil tank is communicated with the oil pump, the oil pump is communicated with the main oil cavity one and the main oil cavity four through the oil pipe one and the steering gear control valve, and the steering gear control valve is communicated with the oil tank through the oil pipe two.

[0013] Further, the control valve group includes the electromagnetic valve four, the electromagnetic valve five and the electromagnetic valve six, the oil pump adopts a double pump, the double pump includes a main pump and an auxiliary pump, the main pump is communicated with the oil pipe one, the main pump is further communicated with the oil pipe two through the overflow valve one, the auxiliary pump is communicated with the accumulator through the electromagnetic valve four, the electromagnetic valve five and the electromagnetic valve six in sequence, and the accumulator is communicated with the oil pipe two through the overflow valve three.

[0014] The auxiliary pump is arranged, so that the accumulator can be independently supplemented with oil, and the function of the control system is increased.

[0015] Further, the electromagnetic valve four is a three-position four-way valve, the electromagnetic valve four is communicated with the oil pipe two, the control valve group further includes the electromagnetic valve seven, the auxiliary pump is communicated with the auxiliary oil cavity one through the electromagnetic valve four and the electromagnetic valve seven, the auxiliary oil cavity one is communicated with the oil tank through the electromagnetic valve seven, the electromagnetic valve four and the oil pipe two, the auxiliary pump is further communicated with the auxiliary oil cavity two through the electromagnetic valve four and the electromagnetic valve five, and the auxiliary oil cavity two is communicated with the oil tank through the electromagnetic valve five, the electromagnetic valve four and the oil pipe two.

[0016] The application can adjust the position of the piston rod of the centering oil cylinder through the auxiliary pump, can avoid the problem of dragging and sliding of the rear wheel in the deflection state when the vehicle is driving straight, and can affect the vehicle handling and safety.

[0017] The application further provides a driven rear axle, comprising an axle body provided with a suspension and a knuckle arm, and a control system of the driven rear axle, wherein the suspension is a single pendulum arm type air suspension, the piston rod of the centering oil cylinder is connected with the knuckle arm of the rear axle, and the cylinder body of the centering oil cylinder is rotatably arranged on the axle body.

[0018] The application further provides a control method of the driven rear axle, which comprises the following contents.

[0019] When the driving speed of the vehicle is not higher than the set speed, and the front wheel is right turning, the main oil chamber one of the main oil cylinder is controlled to admit oil, the main oil chamber four is controlled to return oil, the piston rod of the main oil cylinder is controlled to move right, the oil in the main oil chamber two is controlled to be squeezed into the auxiliary oil chamber one through the electromagnetic valve one, the piston rod of the centering oil cylinder is controlled to move, the oil in the auxiliary oil chamber two is controlled to be returned to the main oil chamber three through the electromagnetic valve three, the oil in the auxiliary oil chamber four is controlled to be compressed, a part of the oil is controlled to be supplemented into the auxiliary oil chamber three, and a part of the oil is controlled to be supplemented into the accumulator, so that the driven rear axle wheel is left deflected; when the front wheel is left turning, the main oil chamber four of the main oil cylinder is controlled to admit oil, the main oil chamber one is controlled to return oil, the piston rod of the main oil cylinder is controlled to move left, the oil in the main oil chamber three is controlled to be squeezed into the auxiliary oil chamber two through the electromagnetic valve three, the oil in the auxiliary oil chamber one is controlled to be returned to the main oil chamber two through the electromagnetic valve one, the oil in the auxiliary oil chamber three is controlled to be compressed and supplemented into the auxiliary oil chamber four, and a part of the oil in the accumulator is also supplemented into the auxiliary oil chamber four, so that the driven rear axle wheel is right deflected; when the vehicle is driving straight, the main oil chamber two and the main oil chamber three are controlled to be communicated through the electromagnetic valve two, the electromagnetic valve one and the electromagnetic valve three are not communicated, the auxiliary oil chamber three and the auxiliary oil chamber four are controlled to be communicated with the accumulator, the floating piston one and the floating piston two are controlled to be balanced on the limiting block under the pressure of the accumulator, the position of the piston rod of the centering oil cylinder is controlled to be centered and immovable, and the driven rear axle wheel is in the driving straight state.

[0020] When the driving speed of the vehicle is higher than the set speed, the driven axle does not need to be steered, the electromagnetic valve one and the electromagnetic valve three are not communicated, the electromagnetic valve two is communicated, the position of the piston rod of the centering oil cylinder is detected, if the position of the piston rod of the centering oil cylinder causes the right deflection of the rear wheel, the oil of the auxiliary pump is controlled to be returned to the auxiliary oil chamber one through the electromagnetic valve four and the electromagnetic valve seven, the oil in the auxiliary oil chamber two is controlled to be returned to the oil tank through the electromagnetic valve five and the electromagnetic valve four, and the position of the piston rod is centered; if the position of the piston rod of the centering oil cylinder causes the left deflection of the rear wheel, the oil of the auxiliary pump is controlled to be returned to the auxiliary oil chamber two through the electromagnetic valve four and the electromagnetic valve five, the oil in the auxiliary oil chamber one is controlled to be returned to the oil tank through the electromagnetic valve seven and the electromagnetic valve four, and the position of the piston rod is centered.

[0021] The application realizes the simultaneous steering of the rear axle and the steering wheel during low-speed driving, improves the passability of the whole vehicle, prevents the rear axle from deflecting during straight driving to avoid the wear of the rear axle wheel, and has the beneficial effect of preventing the deflection of the rear axle from affecting the control of the whole vehicle during high-speed driving.

[0022] Further, when the accumulator needs to be refilled, the position of the centering cylinder piston rod is detected, and if it is not in the centering position, it is adjusted to be in the centering position, the electromagnetic valve 7 is in the off state, and the oil pumped by the auxiliary pump passes through the electromagnetic valve 4, the electromagnetic valve 5 and the electromagnetic valve 6 to the accumulator, and the excess oil in the accumulator returns to the oil tank through the overflow valve 3.

[0023] The application also has the function of refilling the accumulator, and can still ensure that the rear axle does not deflect when the oil in the accumulator is insufficient, thereby improving the reliability.

[0024] From the above technical solution, the application has the following advantages:

[0025] The application provides a control system of a driven rear axle, a driven rear axle and a driven rear axle control method, which can drive the centering cylinder to act by the driving cylinder during steering, realize the active steering of the driven rear axle, and avoid the passive steering of the driven axle under the action of the road friction to cause the wear of the tire; the accumulator, the floating piston 1 and the floating piston 2 can limit the position of the centering cylinder piston rod, ensure that it is in the center position, do not control the steering of the rear axle, and are suitable for the working conditions of straight driving and high-speed driving of the whole vehicle, thereby avoiding the wear caused by the deflection of the rear axle tire and increasing the difficulty of the control of the whole vehicle; the stroke sensor can sense the position of the centering cylinder piston rod, and then judge whether the rear axle wheel deflects and the deflection direction, form a closed loop control, and improve the working reliability and accuracy of the system; the auxiliary pump can independently supplement the oil of the accumulator, and increase the function of the control system; the auxiliary pump is communicated with the auxiliary oil cavity 1 and the auxiliary oil cavity 2, and the auxiliary oil cavity 1 and the auxiliary oil cavity 2 can be communicated with the oil tank, the position of the centering cylinder piston rod can be adjusted by the auxiliary pump to avoid the problem of the deflection state of the rear wheel during straight driving, and affect the controllability and safety of the whole vehicle; the application also has the function of refilling the accumulator, and can still ensure that the rear axle does not deflect when the oil in the accumulator is insufficient, thereby improving the reliability. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the application, the drawings needed in the description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0027] Figure 1The schematic diagram of the principle of the control valve group in the embodiment one of the present application.

[0028] Figure 2 The schematic diagram of the principle of the control valve group in the embodiment one of the present application.

[0029] Figure 3 The main oil cylinder in the embodiment one of the present application.

[0030] Figure 4 The centering oil cylinder in the embodiment one of the present application.

[0031] In the figure, 1, main pump; 2, main oil cylinder; 21, main oil cavity one; 22, main oil cavity two; 23, main oil cavity three; 24, main oil cavity four; 3, diverter control valve; 4, centering oil cylinder; 41, auxiliary oil cavity one; 42, auxiliary oil cavity two; 43, auxiliary oil cavity three; 44, auxiliary oil cavity four; 45, limit block; 46, floating piston two; 47, floating piston one; 5, accumulator; 6, control valve group; 60, electromagnetic valve four; 61, electromagnetic valve five; 62, electromagnetic valve seven; 63, electromagnetic valve six; 64, electromagnetic valve three; 66, electromagnetic valve two; 67, electromagnetic valve one; 68, overflow valve three; 7, overflow valve one; 8, overflow valve two; 9, oil pipe two; 10, oil pipe one; 11, auxiliary pump; 12, oil tank; 13, partition plate. Embodiment

[0032] In order to make the purpose, features and advantages of the present application more obvious and easy to understand, the technical solutions in the present application will be described clearly and completely below in combination with the drawings in the embodiment. Obviously, the following described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present patent, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present patent. Embodiment one

[0034] As Figure 1 , Figure 3 and Figure 4As shown, this specific embodiment provides a control system for a driven rear axle, including an active oil cylinder 2 and a centering oil cylinder 4. The piston rod of the active oil cylinder 2 is used to connect with the swing arm of the steering system. A partition 13 is provided in the cylinder body of the active oil cylinder 2. Its piston rod passes through the partition 13 and can move axially. Two pistons are provided on the piston rod, which divides the cylinder body of the active oil cylinder 2 into a main oil chamber 1 21, a main oil chamber 2 22, a main oil chamber 3 23 and a main oil chamber 4 24. The main oil chamber 1 21 and the main oil chamber 4 24 are both connected to the oil tank 12 through the steering gear control valve 3. The steering gear control valve 3 is connected to the oil pump of the oil tank 12 through the oil pipe 10 to realize oil inlet, and is connected to the oil tank through the oil pipe 2 9. 12 is connected to return oil, and the steering gear control valve 3 can switch the oil flow direction of the active oil chamber 1 and the active oil chamber 4, and exchange the oil inlet and return of the two; the piston rod of the centering cylinder 4 is used to connect with the steering knuckle arm of the rear axle, and a partition 13 is provided in the cylinder body of the centering cylinder 4. Its piston rod passes through the partition 13 and can move axially. Two pistons are provided on the piston rod, which divides the cylinder body of the centering cylinder 4 into auxiliary oil chamber 1 41, auxiliary oil chamber 2 42, auxiliary oil chamber 3 43 and auxiliary oil chamber 4 44. The auxiliary oil chamber 1 41 and the main oil chamber 2 22 are connected through the control valve group 6, the auxiliary oil chamber 2 42 and the main oil chamber 3 23 are connected through the control valve group 6, and the auxiliary oil chamber 3 43 and the auxiliary oil chamber 4 44 are connected.

[0035] Through the cooperation between the active oil cylinder 2 and the centering oil cylinder 4, this specific embodiment can, when turning, first drive the active oil cylinder 2 to perform corresponding actions through the steering gear control valve 3, and the oil in the active oil cylinder 2 drives the centering oil cylinder 4 to drive the centering oil cylinder 4 to act, thereby realizing active steering of the driven rear axle, avoiding the passive steering of the driven axle under the action of road friction, its turning angle is uncontrollable, and wear and tear on the tires.

[0036] like Figure 1 As shown, in this specific embodiment, the control valve group 6 includes a solenoid valve 1 67 and a solenoid valve 3 64 , the main oil chamber 2 22 is connected to the auxiliary oil chamber 1 41 through the solenoid valve 1 67 , and the main oil chamber 3 23 is connected to the auxiliary oil chamber 2 42 through the solenoid valve 3 64 .

[0037] like Figure 1As shown, under the straight running condition of the whole vehicle, the wheels of the rear axle are not desired to follow the deflection of the front wheels, because the tire will be worn out. Meanwhile, under the high speed running condition, the wheels of the rear axle are not desired to deflect, in order to ensure the steering of the whole vehicle. Therefore, the embodiment further comprises an accumulator 5, and the sub-oil chamber three 43 and the sub-oil chamber four 44 are in communication with the accumulator 5. In this way, the pressure in the sub-oil chamber three 43 and the sub-oil chamber four 44 is the pressure of the accumulator 5, and the floating piston one 47 and the floating piston two 46 are arranged in the cylinder body of the centering oil cylinder 4 and can move axially along the cylinder body. The piston rod of the centering oil cylinder 4 penetrates the floating piston one 47, the floating piston one 47 is arranged in the sub-oil chamber three 43, and the floating piston two 46 is arranged in the sub-oil chamber four 44. The cylinder body of the centering oil cylinder 4 is fixedly provided with a limiting block 45. The control valve group 6 further comprises a solenoid valve two 66, and the main oil chamber two 22 and the main oil chamber three 23 are in communication through the solenoid valve two 66. The floating piston one 47 and the floating piston two 46 can abut against the limiting block 45 on both sides under the action of the pressure of the accumulator 5. In this way, the piston of the centering oil cylinder 4 is clamped between the floating piston one 47 and the floating piston two 46 to achieve limiting. At this time, the centering oil cylinder 4 is in the centering position, and the wheels corresponding to the rear axle do not deflect to achieve steering locking. The centering oil cylinder 4 is provided with a stroke sensor, the position of the piston rod of the centering oil cylinder 4 can be sensed through the stroke sensor, and whether the wheels of the rear axle deflect and the deflection direction can be judged, so as to form a closed loop control and improve the working reliability and accuracy of the system.

[0038] As shown in the figure, Figure 1 In the embodiment, the oil tank 12 is in communication with an oil pump, the oil pump is in communication with the main oil chamber one 21 and the main oil chamber four 24 through the oil pipe one 10 and the steering gear control valve 3, and the steering gear control valve 3 is in communication with the oil tank 12 through the oil pipe two 9.

[0039] As shown in the figure, Figure 1 Since the accumulator 5 leaks oil during long-term use, it cannot guarantee the centering position of the centering oil cylinder 4 when needed. In order to supplement oil in time, the control valve group 6 comprises a solenoid valve four 60, a solenoid valve five 61 and a solenoid valve six 63 in the embodiment. The oil pump adopts a duplex pump, which comprises a main pump 1 and a sub-pump 11. The main pump 1 is in communication with the oil pipe one 10, and the main pump 1 is also in communication with the oil pipe two 9 through the overflow valve one 7. The sub-pump 11 is in communication with the accumulator 5 through the solenoid valve four 60, the solenoid valve five 61 and the solenoid valve six 63 in sequence. The accumulator 5 is in communication with the oil pipe two 9 through the overflow valve three 68. The sub-pump 11 is also in communication with the oil pipe two 9 through the overflow valve two 8.

[0040] As shown in the figure, Figure 1As shown, when driving at high speed, the front wheels steering will drive the rear axle wheels to rotate, which will cause the vehicle handling performance to decline, and thus, the rear axle steering function needs to be locked when driving at high speed. To this end, in the specific embodiment, the electromagnetic valve four 60 is a three-position four-way valve, the electromagnetic valve four 60 is communicated with the oil pipe two 9 to enable the oil to return to the oil tank 12, the control valve group 6 further includes an electromagnetic valve seven 62, the auxiliary pump 11 is communicated with the auxiliary oil chamber one 41 through the electromagnetic valve four 60 and the electromagnetic valve seven 62, and the auxiliary pump 11 is further communicated with the auxiliary oil chamber two 42 through the electromagnetic valve four 60 and the electromagnetic valve five 61; by communicating the auxiliary pump 11 with the auxiliary oil chamber one 41 and the auxiliary oil chamber two 42, and the auxiliary oil chamber one 41 and the auxiliary oil chamber two 42 being capable of returning oil to the oil tank 12, the oil supplement through the auxiliary pump 11 is realized, the position of the piston rod of the centering oil cylinder 4 is adjusted, the central position is ensured, the rear wheel deflection state drag and slip problem when the vehicle is driving straight is avoided, and the vehicle handling performance and safety are affected. Specific embodiment two

[0042] The specific embodiment provides a driven rear axle, which comprises an axle body, a suspension and a knuckle arm arranged on the axle body, and a control system of the driven rear axle of the specific embodiment one, the suspension is an air suspension of a single swing arm type, a piston rod of the centering oil cylinder 4 is connected with the knuckle arm of the rear axle, and a cylinder body of the centering oil cylinder 4 is rotatably arranged on the axle body through a ball hinge.

[0043] The suspension comprises a guide arm, an air bag, a shock absorber, a guide arm support, a connecting cross beam and a transverse thrust rod, there are one guide arm on the left and one guide arm on the right, which are connected to the suspension mounting interface at the lower wing surface part of the driven rear axle support shaft, the front ends of the guide arms are connected with the left and right longitudinal beams of the vehicle frame through the left and right guide arm supports respectively, and the rear ends of the guide arms are connected together through the transversely arranged connecting cross beam; one air bag is fixed on the left side and one air bag is fixed on the right side of the upper part of the connecting cross beam, and the upper parts of the air bags are connected to the lower wing surfaces of the left and right longitudinal beams of the vehicle frame; there are one shock absorber on the left and one shock absorber on the right, the lower ends of the shock absorbers are fixedly installed at the rear side air bag front part of the connection part of the guide arms and the support shaft, and the upper ends of the shock absorbers are connected to the left and right longitudinal beams of the vehicle frame; one end of the transverse thrust rod is connected to the thrust rod connecting interface on the driven rear axle, and the other end of the transverse thrust rod is connected to the longitudinal beam of the vehicle frame. The guide arm, the air bag and the shock absorber of the suspension system are used to solve the vertical direction vibration and impact of the vehicle during driving; the transverse thrust rod is used to solve the lateral displacement of the driven rear axle under the lateral force working condition of the vehicle, to reduce the deformation of the air bag caused by the lateral displacement of the driven rear axle, and to improve the stress state of the air bag. Specific embodiment three

[0045] As shown in Figure 1 and Figure 2 The specific embodiment provides a control method of a driven rear axle, which adopts the driven rear axle described above, and includes the following contents:

[0046] When the vehicle is running at a speed not higher than the set speed, if the front wheels turn right, the solenoid valve 1 67 and the solenoid valve 3 64 are turned on, the solenoid valve 2 66, the solenoid valve 4 60, the solenoid valve 5 61, the solenoid valve 6 63 and the solenoid valve 7 62 are all turned off, the main oil chamber 1 21 of the main cylinder 2 is controlled to admit oil, the main oil chamber 4 24 is controlled to return oil, the piston rod of the main cylinder 2 moves right, the oil in the main oil chamber 2 22 is squeezed into the auxiliary oil chamber 1 41 through the solenoid valve 1 67, the piston rod of the centering cylinder 4 is moved, the oil in the auxiliary oil chamber 2 42 is squeezed into the main oil chamber 3 23 through the solenoid valve 3 64, the oil in the auxiliary oil chamber 4 44 is compressed, part of which is supplemented into the auxiliary oil chamber 3 43 and part of which is supplemented into the accumulator 5, and the driven rear wheels turn left; if the front wheels turn left, the main oil chamber 4 24 of the main cylinder 2 is controlled to admit oil, the main oil chamber 1 21 is controlled to return oil, the piston rod of the main cylinder 2 moves left, the oil in the main oil chamber 3 23 is squeezed into the auxiliary oil chamber 2 42 through the solenoid valve 3 64, the oil in the auxiliary oil chamber 1 41 is squeezed into the main oil chamber 2 22 through the solenoid valve 1 67, the oil in the auxiliary oil chamber 3 43 is compressed and supplemented into the auxiliary oil chamber 4 44, and part of the oil in the accumulator 5 is also supplemented into the auxiliary oil chamber 4 44, so that the driven rear wheels turn right; when the vehicle is running straight, the main oil chamber 2 22 and the main oil chamber 3 23 are controlled to communicate through the solenoid valve 2 66, the solenoid valve 1 67 and the solenoid valve 3 64 are not communicated, the auxiliary oil chamber 3 43 and the auxiliary oil chamber 4 44 are controlled to communicate with the accumulator 5, the floating piston 1 47 and the floating piston 2 46 are balanced on the limiting block 45 under the pressure of the accumulator 5, the position of the piston rod of the centering cylinder 4 is centered and cannot be moved, and the driven rear wheels are in a straight running state.

[0047] When the vehicle is running at a speed higher than the set speed, in order to ensure the maneuverability of the vehicle, the driven rear wheels do not need to be steered, the solenoid valve 1 67 and the solenoid valve 3 64 are not turned on, and the solenoid valve 2 66 is turned on; when it is detected that the position of the piston rod of the centering cylinder 4 causes the rear wheels to turn right, the solenoid valve 4 60 and the solenoid valve 7 62 are controlled to communicate, the solenoid valve 7 62 and the solenoid valve 5 61 are turned on, the oil in the auxiliary pump 1 1 is squeezed into the auxiliary oil chamber 1 41 through the solenoid valve 4 60 and the solenoid valve 7 62, the oil in the auxiliary oil chamber 2 42 is returned to the oil tank 12 through the solenoid valve 5 61 and the oil pipe 2 9, and the position of the piston rod is centered; when it is detected that the position of the piston rod of the centering cylinder 4 causes the rear wheels to turn left, the solenoid valve 4 60 and the solenoid valve 5 61 are controlled to communicate, the solenoid valve 5 61 and the solenoid valve 7 62 are turned on, the oil in the auxiliary pump 1 1 is squeezed into the auxiliary oil chamber 2 42 through the solenoid valve 4 60 and the solenoid valve 5 61, the oil in the auxiliary oil chamber 1 41 is returned to the oil tank 12 through the solenoid valve 7 62 and the oil pipe 2 9, and the position of the piston rod is centered.

[0048] During long-term use of the hydraulic system, a small amount of oil inevitably leaks from the accumulator 5, the pressure decreases, and the centering oil cylinder 4, which should be in the neutral state, is not in the neutral state, that is, the rear driven axle wheels deviate slightly from the straight running state and need to be corrected. The wheel position correction needs to be operated in the stationary state of the vehicle. When the rear driven axle wheels deviate slightly to the left, the adjustment process is the same as that when the rear driven axle wheels deviate to the left at high speed. When the rear driven axle wheels deviate slightly to the right, the adjustment process is the same as that when the rear driven axle wheels deviate to the right at high speed.

[0049] When the accumulator 5 needs to be refilled, the position of the centering oil cylinder 4 piston rod is detected, and if it is not in the central position, it is adjusted to the central position. The adjustment method is the same as the above wheel position correction process. After adjustment, the electromagnetic valve seven 62 is in the off state, the electromagnetic valve four 60 and the electromagnetic valve five 61 are connected, the electromagnetic valve five 61 and the electromagnetic valve six 63 are both on, and the oil pumped by the auxiliary pump 11 passes through the electromagnetic valve four 60, the electromagnetic valve five 61 and the electromagnetic valve six 63 to the accumulator 5. The excess oil in the accumulator 5 returns to the oil tank 12 through the overflow valve three 68.

[0050] In the specific embodiment, the position of the centering oil cylinder 4 piston rod and the deflection angle of the rear axle wheels are calibrated and set. The speed is determined according to the overall working condition of the vehicle and the overall vehicle condition.

[0051] As can be seen from the above specific embodiment, the present application has the following beneficial effects:

[0052] 1. The driven rear axle can follow the active steering function of the front wheels, which can effectively reduce the minimum steering circle diameter of the vehicle and improve the passability of the vehicle. This function is mainly used for low-speed and off-road working conditions to avoid passive steering of the driven axle under the action of road friction and tire wear.

[0053] 2. By connecting the auxiliary pump 11 with the auxiliary oil chamber one 41 and the auxiliary oil chamber two 42, and connecting the auxiliary oil chamber one 41 and the auxiliary oil chamber two 42 with the oil tank 12, the position of the centering oil cylinder 4 piston rod can be adjusted by refilling the auxiliary pump 11, avoiding the deflection of the rear axle wheels driven by the front wheels at high speed, affecting the handling and safety of the vehicle, realizing the locking of the rear axle at high speed to ensure straight running, without the need for complex locking mechanisms, and also being able to correct the wheel position of the rear axle.

[0054] 3. By providing the auxiliary pump 11, the accumulator 5 can be independently refilled with oil, increasing the function of the control system.

[0055] 4. It also has the function of refilling the accumulator 5 with oil and can still ensure that the rear axle does not deviate when the oil in the accumulator 5 is insufficient, improving reliability.

[0056] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control system of a driven rear axle, comprising a main cylinder (2) and a centering cylinder (4), characterized in that: a piston rod of the main cylinder (2) is used to connect with a swing arm of a steering system, the main cylinder (2) comprises a main oil chamber one (21), a main oil chamber two (22), a main oil chamber three (23) and a main oil chamber four (24), the main oil chamber one (21) and the main oil chamber four (24) are communicated through a steering gear control valve (3), the steering gear control valve can switch the oil inlet and the oil return of the main oil chamber one (21) and the main oil chamber four (24), the steering gear control valve (3) is communicated with an oil tank (12); a piston rod of the centering cylinder (4) is used to connect with a knuckle arm of the rear axle, the centering cylinder (4) comprises a secondary oil chamber one (41), a secondary oil chamber two (42), a secondary oil chamber three (43) and a secondary oil chamber four (44), the secondary oil chamber one (41) and the main oil chamber two (22) are communicated through a control valve group (6), the secondary oil chamber two (42) and the main oil chamber three (23) are communicated through the control valve group (6), the secondary oil chamber three (43) and the secondary oil chamber four (44) are communicated; the control valve group (6) comprises a solenoid valve one (67), a solenoid valve two (66) and a solenoid valve three (64), the main oil chamber two (22) is communicated with the secondary oil chamber one (41) through the solenoid valve one (67), the main oil chamber three (23) is communicated with the secondary oil chamber two (42) through the solenoid valve three (64), the main oil chamber two (22) and the main oil chamber three (23) are communicated through the solenoid valve three (64); further comprising an accumulator (5); the oil tank (12) is provided with an oil pump, the oil pump is communicated with the main oil chamber one (21) and the main oil chamber four (24) through an oil pipe one (10) and the steering gear control valve (3), the steering gear control valve (3) is communicated with the oil tank (12) through an oil pipe two (9); the control valve group (6) comprises a solenoid valve four (60), a solenoid valve five (61) and a solenoid valve six (63), the oil pump adopts a double pump, the double pump comprises a main pump (1) and a secondary pump (11), the main pump (1) is communicated with the oil pipe one (10), the main pump (1) is further communicated with the oil pipe two (9) through a relief valve one (7), the secondary pump (11) is communicated with the accumulator (5) through the solenoid valve four (60), the solenoid valve five (61) and the solenoid valve six (63) in turn, the accumulator (5) is communicated with the oil pipe two (9) through a relief valve three (68); the solenoid valve four (60) is a three-position four-way valve, the solenoid valve four (60) is communicated with the oil pipe two (9), the control valve group (6) further comprises a solenoid valve seven (62), the secondary pump (11) is communicated with the secondary oil chamber one (41) through the solenoid valve four (60) and the solenoid valve seven (62), the secondary pump (11) is further communicated with the secondary oil chamber two (42) through the solenoid valve four (60) and the solenoid valve five (61).

2. The control system of a driven rear axle as set forth in claim 1, characterized in that: The auxiliary oil cavity three (43) and the auxiliary oil cavity four (44) are communicated with the accumulator (5), the cylinder body of the centering oil cylinder (4) is provided with a floating piston one (47) and a floating piston two (46), the floating piston one (47) penetrates the piston rod of the centering oil cylinder (4) and is located in the auxiliary oil cavity three (43), the cylinder body of the centering oil cylinder (4) is provided with a limiting block (45), the floating piston one (47) and the floating piston two (46) can abut on both sides of the limiting block (45), the floating piston two (46) is arranged in the auxiliary oil cavity four (44), the main oil cavity two (22) and the main oil cavity two (22) are communicated through the control valve group (6).

3. The control system of a driven rear axle as set forth in claim 2, characterized in that: The centering oil cylinder (4) is provided with a stroke sensor.

4. A driven rear axle comprising an axle body having a suspension and a knuckle arm disposed thereon, characterized by: The control system of the driven rear axle as claimed in claim 3 is further provided with a single swing arm type air suspension, a piston rod of the centering oil cylinder (4) is connected with a knuckle arm of the rear axle, and a cylinder body of the centering oil cylinder (4) is rotatably arranged on the axle body.

5. A control method of a driven rear axle, characterized by: The driven rear axle as claimed in claim 4 is further provided with the following contents: When the driving speed of the vehicle is not higher than the set speed, and the front wheel turns right, the main oil cavity one of the main oil cylinder is controlled to input oil, the main oil cavity four is controlled to output oil, the piston rod of the main oil cylinder moves right, the oil in the main oil cavity two is squeezed to the auxiliary oil cavity one through the electromagnetic valve one, the piston rod of the centering oil cylinder moves, the oil in the auxiliary oil cavity two is input to the main oil cavity three through the electromagnetic valve three, the oil in the auxiliary oil cavity four is compressed, part of the oil is supplemented to the auxiliary oil cavity three, and part of the oil is supplemented to the accumulator, so that the wheel of the driven rear axle deflects left; when the front wheel turns left, the main oil cavity four of the main oil cylinder is controlled to input oil, the main oil cavity one is controlled to output oil, the piston rod of the main oil cylinder moves left, the oil in the main oil cavity three is squeezed to the auxiliary oil cavity two through the electromagnetic valve three, the oil in the auxiliary oil cavity one is input to the main oil cavity two through the electromagnetic valve one, the oil in the auxiliary oil cavity three is compressed and supplemented to the auxiliary oil cavity four, and part of the oil of the accumulator is also supplemented to the auxiliary oil cavity four, so that the wheel of the driven rear axle deflects right; when the vehicle drives straight, the main oil cavity two and the main oil cavity three are controlled to be communicated through the electromagnetic valve two, the electromagnetic valve one and the electromagnetic valve three are not conducted, the auxiliary oil cavity three and the auxiliary oil cavity four are communicated with the accumulator, the floating piston one and the floating piston two are balanced on the limiting block under the pressure of the accumulator, the position of the piston rod of the centering oil cylinder is in the middle and cannot move, and the wheel of the driven rear axle is in the straight driving state; When the driving speed of the vehicle is higher than the set speed, the electromagnetic valve one and the electromagnetic valve three are not conducted, the electromagnetic valve two is conducted, the position of the piston rod of the centering oil cylinder is detected, if the position of the piston rod of the centering oil cylinder causes the rear wheel to deflect right, the oil of the auxiliary pump is input to the auxiliary oil cavity one through the electromagnetic valve four and the electromagnetic valve seven, the oil in the auxiliary oil cavity two is output to the oil tank through the electromagnetic valve five and the electromagnetic valve four, and the position of the piston rod is in the middle; when it is detected that the position of the piston rod of the centering oil cylinder causes the rear wheel to deflect left, the oil of the auxiliary pump is input to the auxiliary oil cavity two through the electromagnetic valve four and the electromagnetic valve five, the oil in the auxiliary oil cavity one is output to the oil tank through the electromagnetic valve seven and the electromagnetic valve four, and the position of the piston rod is in the middle.

6. The control method of the driven rear axle according to claim 5, characterized by: When the accumulator needs to be refilled, the position of the oil cylinder piston rod is detected, and if it is not in the center position, it is adjusted to the center position, and then the electromagnetic valve seven is in the off state, and the oil pumped by the auxiliary pump is discharged to the accumulator through electromagnetic valve four, electromagnetic valve five and electromagnetic valve six, and the excess oil in the accumulator returns to the oil tank through overflow valve three.

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